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/*
* Copyright (C) 2015, 2016 "IoT.bzh"
* Author "Fulup Ar Foll"
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <time.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <uuid/uuid.h>
#include <assert.h>
#include <errno.h>
#include <json-c/json.h>
#include "session.h"
#include "verbose.h"
#define NOW (time(NULL))
struct client_value
{
void *value;
void (*free_value)(void*);
};
struct afb_event_listener_list
{
struct afb_event_listener_list *next;
struct afb_event_listener listener;
int refcount;
};
struct AFB_clientCtx
{
unsigned refcount;
unsigned loa;
time_t expiration; // expiration time of the token
time_t access;
char uuid[37]; // long term authentication of remote client
char token[37]; // short term authentication of remote client
struct client_value *values;
struct afb_event_listener_list *listeners;
};
// Session UUID are store in a simple array [for 10 sessions this should be enough]
static struct {
pthread_mutex_t mutex; // declare a mutex to protect hash table
struct AFB_clientCtx **store; // sessions store
int count; // current number of sessions
int max;
int timeout;
int apicount;
char initok[37];
struct afb_event_listener_list *listeners;
} sessions;
/* generate a uuid */
static void new_uuid(char uuid[37])
{
uuid_t newuuid;
uuid_generate(newuuid);
uuid_unparse_lower(newuuid, uuid);
}
// Free context [XXXX Should be protected again memory abort XXXX]
static void ctxUuidFreeCB (struct AFB_clientCtx *client)
{
int idx;
// If application add a handle let's free it now
assert (client->values != NULL);
// Free client handle with a standard Free function, with app callback or ignore it
for (idx=0; idx < sessions.apicount; idx ++)
ctxClientValueSet(client, idx, NULL, NULL);
}
// Create a new store in RAM, not that is too small it will be automatically extended
void ctxStoreInit (int max_session_count, int timeout, const char *initok, int context_count)
{
// let's create as store as hashtable does not have any
sessions.store = calloc (1 + (unsigned)max_session_count, sizeof(struct AFB_clientCtx));
sessions.max = max_session_count;
sessions.timeout = timeout;
sessions.apicount = context_count;
if (initok == NULL)
/* without token, a secret is made to forbid creation of sessions */
new_uuid(sessions.initok);
else if (strlen(initok) < sizeof(sessions.store[0]->token))
strcpy(sessions.initok, initok);
else {
ERROR("initial token '%s' too long (max length 36)", initok);
exit(1);
}
}
static struct AFB_clientCtx *ctxStoreSearch (const char* uuid)
{
int idx;
struct AFB_clientCtx *client;
assert (uuid != NULL);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
client = sessions.store[idx];
if (client && (0 == strcmp (uuid, client->uuid)))
goto found;
}
client = NULL;
found:
pthread_mutex_unlock(&sessions.mutex);
return client;
}
static int ctxStoreDel (struct AFB_clientCtx *client)
{
int idx;
int status;
assert (client != NULL);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
if (sessions.store[idx] == client) {
sessions.store[idx] = NULL;
sessions.count--;
status = 1;
goto deleted;
}
}
status = 0;
deleted:
pthread_mutex_unlock(&sessions.mutex);
return status;
}
static int ctxStoreAdd (struct AFB_clientCtx *client)
{
int idx;
int status;
assert (client != NULL);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
if (NULL == sessions.store[idx]) {
sessions.store[idx] = client;
sessions.count++;
status = 1;
goto added;
}
}
status = 0;
added:
pthread_mutex_unlock(&sessions.mutex);
return status;
}
// Check if context timeout or not
static int ctxStoreTooOld (struct AFB_clientCtx *ctx, time_t now)
{
assert (ctx != NULL);
return ctx->expiration < now;
}
// Check if context is active or not
static int ctxIsActive (struct AFB_clientCtx *ctx, time_t now)
{
assert (ctx != NULL);
return ctx->uuid[0] != 0 && ctx->expiration >= now;
}
// Loop on every entry and remove old context sessions.hash
static void ctxStoreCleanUp (time_t now)
{
struct AFB_clientCtx *ctx;
long idx;
// Loop on Sessions Table and remove anything that is older than timeout
for (idx=0; idx < sessions.max; idx++) {
ctx = sessions.store[idx];
if (ctx != NULL && ctxStoreTooOld(ctx, now)) {
ctxClientClose (ctx);
}
}
}
// This function will return exiting client context or newly created client context
struct AFB_clientCtx *ctxClientGetSession (const char *uuid, int *created)
{
struct AFB_clientCtx *clientCtx;
time_t now;
/* cleaning */
now = NOW;
ctxStoreCleanUp (now);
/* search for an existing one not too old */
if (uuid != NULL) {
if (strlen(uuid) >= sizeof clientCtx->uuid) {
errno = EINVAL;
goto error;
}
clientCtx = ctxStoreSearch(uuid);
if (clientCtx != NULL) {
*created = 0;
goto found;
}
}
/* returns a new one */
clientCtx = calloc(1, sizeof(struct AFB_clientCtx) + ((unsigned)sessions.apicount * sizeof(*clientCtx->values)));
if (clientCtx == NULL) {
errno = ENOMEM;
goto error;
}
clientCtx->values = (void*)(clientCtx + 1);
/* generate the uuid */
if (uuid == NULL) {
new_uuid(clientCtx->uuid);
} else {
strcpy(clientCtx->uuid, uuid);
}
/* init the token */
strcpy(clientCtx->token, sessions.initok);
clientCtx->expiration = now + sessions.timeout;
if (!ctxStoreAdd (clientCtx)) {
errno = ENOMEM;
goto error2;
}
*created = 1;
found:
clientCtx->access = now;
clientCtx->refcount++;
return clientCtx;
error2:
free(clientCtx);
error:
return NULL;
}
struct AFB_clientCtx *ctxClientAddRef(struct AFB_clientCtx *clientCtx)
{
if (clientCtx != NULL)
clientCtx->refcount++;
return clientCtx;
}
void ctxClientUnref(struct AFB_clientCtx *clientCtx)
{
if (clientCtx != NULL) {
assert(clientCtx->refcount != 0);
--clientCtx->refcount;
if (clientCtx->refcount == 0 && clientCtx->uuid[0] == 0) {
ctxStoreDel (clientCtx);
free(clientCtx);
}
}
}
// Free Client Session Context
void ctxClientClose (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
if (clientCtx->uuid[0] != 0) {
clientCtx->uuid[0] = 0;
ctxUuidFreeCB (clientCtx);
while(clientCtx->listeners != NULL)
ctxClientEventListenerRemove(clientCtx, clientCtx->listeners->listener);
if (clientCtx->refcount == 0) {
ctxStoreDel (clientCtx);
free(clientCtx);
}
}
}
// Sample Generic Ping Debug API
int ctxTokenCheck (struct AFB_clientCtx *clientCtx, const char *token)
{
assert(clientCtx != NULL);
assert(token != NULL);
// compare current token with previous one
if (!ctxIsActive (clientCtx, NOW))
return 0;
if (clientCtx->token[0] && strcmp (token, clientCtx->token) != 0)
return 0;
return 1;
}
// generate a new token and update client context
void ctxTokenNew (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
// Old token was valid let's regenerate a new one
new_uuid(clientCtx->token);
// keep track of time for session timeout and further clean up
clientCtx->expiration = NOW + sessions.timeout;
}
static int add_listener(struct afb_event_listener_list **head, struct afb_event_listener listener)
{
struct afb_event_listener_list *iter, **prv;
prv = head;
for (;;) {
iter = *prv;
if (iter == NULL) {
iter = calloc(1, sizeof *iter);
if (iter == NULL) {
errno = ENOMEM;
return -1;
}
iter->listener = listener;
iter->refcount = 1;
*prv = iter;
return 0;
}
if (iter->listener.itf == listener.itf && iter->listener.closure == listener.closure) {
iter->refcount++;
return 0;
}
prv = &iter->next;
}
}
int ctxClientEventListenerAdd(struct AFB_clientCtx *clientCtx, struct afb_event_listener listener)
{
return add_listener(clientCtx != NULL ? &clientCtx->listeners : &sessions.listeners, listener);
}
static void remove_listener(struct afb_event_listener_list **head, struct afb_event_listener listener)
{
struct afb_event_listener_list *iter, **prv;
prv = head;
for (;;) {
iter = *prv;
if (iter == NULL)
return;
if (iter->listener.itf == listener.itf && iter->listener.closure == listener.closure) {
if (!--iter->refcount) {
*prv = iter->next;
free(iter);
}
return;
}
prv = &iter->next;
}
}
void ctxClientEventListenerRemove(struct AFB_clientCtx *clientCtx, struct afb_event_listener listener)
{
remove_listener(clientCtx != NULL ? &clientCtx->listeners : &sessions.listeners, listener);
}
static int send(struct afb_event_listener_list *head, const char *event, struct json_object *object)
{
struct afb_event_listener_list *iter;
int result;
result = 0;
iter = head;
while (iter != NULL) {
if (iter->listener.itf->expects == NULL || iter->listener.itf->expects(iter->listener.closure, event)) {
iter->listener.itf->send(iter->listener.closure, event, json_object_get(object));
result++;
}
iter = iter->next;
}
return result;
}
int ctxClientEventSend(struct AFB_clientCtx *clientCtx, const char *event, struct json_object *object)
{
long idx;
time_t now;
int result;
now = NOW;
if (clientCtx != NULL) {
result = ctxIsActive(clientCtx, now) ? send(clientCtx->listeners, event, object) : 0;
} else {
result = send(sessions.listeners, event, object);
for (idx=0; idx < sessions.max; idx++) {
clientCtx = ctxClientAddRef(sessions.store[idx]);
if (clientCtx != NULL && ctxIsActive(clientCtx, now)) {
clientCtx = ctxClientAddRef(clientCtx);
result += send(clientCtx->listeners, event, object);
}
ctxClientUnref(clientCtx);
}
}
return result;
}
const char *ctxClientGetUuid (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
return clientCtx->uuid;
}
const char *ctxClientGetToken (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
return clientCtx->token;
}
unsigned ctxClientGetLOA (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
return clientCtx->loa;
}
void ctxClientSetLOA (struct AFB_clientCtx *clientCtx, unsigned loa)
{
assert(clientCtx != NULL);
clientCtx->loa = loa;
}
void *ctxClientValueGet(struct AFB_clientCtx *clientCtx, int index)
{
assert(clientCtx != NULL);
assert(index >= 0);
assert(index < sessions.apicount);
return clientCtx->values[index].value;
}
void ctxClientValueSet(struct AFB_clientCtx *clientCtx, int index, void *value, void (*free_value)(void*))
{
struct client_value prev;
assert(clientCtx != NULL);
assert(index >= 0);
assert(index < sessions.apicount);
prev = clientCtx->values[index];
clientCtx->values[index] = (struct client_value){.value = value, .free_value = free_value};
if (prev.value != NULL && prev.value != value && prev.free_value != NULL)
prev.free_value(prev.value);
}
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